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package org.glassfish.grizzly.attributes;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.glassfish.grizzly.utils.NullaryFunction;

/**
 * Default {@link AttributeBuilder} implementation.
 *
 * @see AttributeBuilder
 * 
 * @author Alexey Stashok
 */
public class DefaultAttributeBuilder implements AttributeBuilder {
    protected final List<Attribute> attributes = new ArrayList<Attribute>();
    protected final Map<String, Attribute> name2Attribute = new HashMap<String, Attribute>();
    
    /**
     * {@inheritDoc}
     */
    @Override
    public synchronized <T> Attribute<T> createAttribute(final String name) {
        return createAttribute(name, (T) null);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    @SuppressWarnings("unchecked")
    public synchronized <T> Attribute<T> createAttribute(final String name,
            final T defaultValue) {
        Attribute<T> attribute = name2Attribute.get(name);
        if (attribute == null) {
            attribute = new Attribute<T>(this, name, attributes.size(), defaultValue);
            attributes.add(attribute);
            name2Attribute.put(name, attribute);
        }
        
        return attribute;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    @SuppressWarnings("unchecked")
    public synchronized <T> Attribute<T> createAttribute(final String name,
            final NullaryFunction<T> initializer) {
        Attribute<T> attribute = name2Attribute.get(name);
        if (attribute == null) {
            attribute = new Attribute<T>(this, name, attributes.size(), initializer);
            attributes.add(attribute);
            name2Attribute.put(name, attribute);
        }
        
        return attribute;
    }

    @Override
    public <T> Attribute<T> createAttribute(final String name,
            final org.glassfish.grizzly.attributes.NullaryFunction<T> initializer) {
        return createAttribute(name, initializer == null ?
                null :
                new NullaryFunction<T>() {

                    @Override
                    public T evaluate() {
                        return initializer.evaluate();
                    }
                });
    }

    @Override
    public AttributeHolder createSafeAttributeHolder() {
        return new IndexedAttributeHolder(this);
    }
    
    @Override
    public AttributeHolder createUnsafeAttributeHolder() {
        return new UnsafeAttributeHolder(this);
    }

    protected Attribute getAttributeByName(final String name) {
        return name2Attribute.get(name);
    }

    protected Attribute getAttributeByIndex(final int index) {
        return attributes.get(index);
    }
}
